Hydraulic System of a Tool

ABSTRACT

An example tool includes a hydraulic actuator cylinder; a piston slidably accommodated within the hydraulic actuator cylinder, where the piston includes a piston head and a piston rod extending from the piston head along a central axis direction of the hydraulic actuator cylinder, the piston head divides an inside of the hydraulic actuator cylinder into a first chamber and a second chamber, and the piston rod is disposed in the first chamber and configured to move one or more jaws of the tool; a pump configured to provide pressurized fluid; and a sequence valve configured to block the pressurized fluid from flowing into the second chamber of the hydraulic actuator cylinder until pressure of the pressurized fluid exceeds a threshold pressure value.

FIELD

The present disclosure relates generally to control of a Hydraulic tool.

BACKGROUND

A powered tool may include one or more movable blades that areactuatable by a hydraulic or electromechanical actuation system. Byproviding power to the actuation system, the blades move relative toeach other to perform operations such as cutting, crimping, separation,blanking, etc.

SUMMARY

The present disclosure describes embodiments that relate to systems,tools, hydraulic circuits, and methods associated with control of ahydraulic tool.

In a first example implementation, the present disclosure describes atool. The tool includes: (i) a hydraulic actuator cylinder; (ii) apiston slidably accommodated within the hydraulic actuator cylinder,where the piston includes a piston head and a piston rod extending fromthe piston head along a central axis direction of the hydraulic actuatorcylinder, the piston head divides an inside of the hydraulic actuatorcylinder into a first chamber and a second chamber, the piston ispartially hollow, and the piston rod is disposed in the first chamberand configured to move one or more jaws of the tool; (iii) a pumpconfigured to provide pressurized fluid; and (iv) a sequence valveconfigured to block the pressurized fluid from flowing into the secondchamber of the hydraulic actuator cylinder until pressure of thepressurized fluid exceeds a threshold pressure value. When the tool istriggered the pump provides the pressurized fluid to a hollow portion ofthe piston, causing the piston to extend at a first speed until at leastone of the one or more jaws reach an object placed therebetween.Thereafter, pressure of the pressurized fluid increases until thepressure reaches the threshold pressure value, causing the sequencevalve to open providing a path for the pressurized fluid to the secondchamber, causing the piston to extend at a second speed.

In a second example implementation, the present disclosure describes ahydraulic circuit. The hydraulic circuit includes (i) a hydraulicactuator cylinder; (ii) a piston slidably accommodated within thehydraulic actuator cylinder, where the piston includes a piston head anda piston rod extending from the piston head along a central axisdirection of the hydraulic actuator cylinder, the piston head divides aninside of the hydraulic actuator cylinder into a first chamber and asecond chamber, the piston is partially hollow, and the piston rod isdisposed in the first chamber; (iii) a pump configured to providepressurized fluid; and (iv) a sequence valve configured to block thepressurized fluid from flowing into the second chamber of the hydraulicactuator cylinder until pressure of the pressurized fluid exceeds athreshold pressure value. The pump provides the pressurized fluid to ahollow portion of the piston, causing the piston to extend at a firstspeed until the piston rod meets a resistance. Thereafter, pressure ofthe pressurized fluid increases until the pressure reaches the thresholdpressure value, causing the sequence valve to open providing a path forthe pressurized fluid to the second chamber, causing the piston toextend at a second speed.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the figures and the followingdetailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a tool, in accordance with an example implementation.

FIG. 2A illustrates a partial cross section of a side or frontal view ofthe tool shown in FIG. 1, in accordance with an example implementation.

FIG. 2B illustrates a partial cross section of a top view of the toolshown in FIG. 1, in accordance with an example implementation.

FIG. 2C illustrates another cross section of the side view of the toolshowing retraction of the piston, in accordance with an exampleimplementation.

FIGS. 2D, 2E, and 2F illustrate operation of a release lever and arelease valve, in accordance with an example implementation

FIG. 3 illustrates a hydraulic circuit of the tool shown in FIG. 1, inaccordance with an example implementation.

DETAILED DESCRIPTION

The following detailed description describes various features andfunctions of the disclosed systems and methods with reference to theaccompanying figures. The illustrative system and method embodimentsdescribed herein are not meant to be limiting. It may be readilyunderstood that certain aspects of the disclosed systems and methods canbe arranged and combined in a wide variety of different configurations,all of which are contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall implementations, with the understanding that not allillustrated features are necessary for each implementation.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to skill in theart, may occur in amounts that do not preclude the effect thecharacteristic was intended to provide.

I. Overview

A powered tool is a tool that is actuated by an additional power sourceand mechanism other than the solely manual labor used with hand tools.Example power tools employ electric motors, hydraulic systems, etc. topower the tool.

A hydraulic tool could be used to cut or crimp cables for example. In anexample, the hydraulic tool may include a cylinder and pistonconfiguration, where the piston is configured to extend and retract, andthus move a blade or any other implement to perform a task (crimping,cutting, etc.).

To make a hydraulic tool more efficient, it is desirable to have a toolwhere the piston could move at variable speeds and apply differentforces based on condition or state of the tool. For instance, the pistonmay be configured to move at a fast speed and apply a small force whiletravelling within its cylinder before a blade coupled to the pistonreaches a cable to be cut. Once the blade reaches the cable, the pistonmay slow down, but cause the blade to apply a larger force to perform acutting operation.

II. Example Tool

FIG. 1 illustrates a tool 100, in accordance with an exampleimplementation. Although the example implementation described hereinreferences an example cutting tool, it should be understood that thefeatures of this disclosure can be implemented in any other tool. Inaddition, any suitable size, shape or type of elements or materialscould be used.

The tool 100 includes an electric motor 102 configured to drive a pump104 by way of a gear reducer 106. The pump 104 is configured to providepressurized hydraulic fluid to a hydraulic actuator cylinder 108, whichincludes a piston slidably accommodated therein. In an example, a frameand a bore of the tool 100 form the hydraulic actuator cylinder 108.

The cylinder 108 has a first end 109A and a second end 109B. The pistonis coupled to a mechanism 110 that is configured to move jaws 112A and112B of a cutting head 114. At least one of the jaws 112A and 112B has ablade such as blade 116. The first end 109A of the cylinder 108 isproximate to the jaws 112A and 112B, whereas the second end 109B isopposite the first end 109A.

When the piston is retracted, the jaws 112A and 112B are pulled back inan open position as shown in FIG. 1. When pressurized fluid is providedto the cylinder 108 by way of the pump 104, the fluid pushes the pistoninside the cylinder 108, and thus the piston extends. As the pistonextends, the mechanism 110 causes the jaws 112A and 112B to move towardeach other, and may thus cause the blade 116 to cut a cable placedbetween the jaws 112A and 112B. When the cutting operation is performed,a lever 118 could be used to release the high pressure fluid back to areservoir as described in details below.

As mentioned above, to make the tool efficient, it may be desirable tohave a tool where the piston could move at variable speeds and applydifferent loads based on state of the tool or the cutting operation. Forinstance, the piston may be configured to advance rapidly at a fastspeed while travelling within the cylinder 108 before the blade 116reaches a cable to be cut. Once the blade reaches the cable, the pistonmay slow down, but cause the blade to apply a large force to perform thecutting operation. Described next is an example hydraulic systemconfigured to control the tool 100.

III. Example Hydraulic System

FIG. 2A illustrates a partial cross section of a side or frontal view ofthe tool 100, in accordance with an example implementation. The tool 100includes a partially hollow piston 200 slidably accommodated within thecylinder 108, which is formed by a frame 201 and a bore 202 of the tool100. The piston 200 includes a piston head 203A and a piston rod 203Bextending from the piston head 203A along a central axis direction ofthe cylinder 108. As shown, the piston 200 is partially hollow.Particularly, the piston head 203A is hollow and the piston rod 203B ispartially hollow, and thus a cylindrical cavity is formed within thepiston 200.

The motor 102 drives the pump 104 to provide pressurized fluid through acheck valve 204 to an extension cylinder 206. The extension cylinder 206is disposed in the cylindrical cavity formed within the partially hollowpiston 200. The piston 200 is configured to slide axially about anexternal surface of the extension cylinder 206. However, the extensioncylinder 206 is affixed to the cylinder 108 at the second end 109B, andthus the extension cylinder 206 does not move with the piston 200.

The piston 200, and particularly the piston rod 203B, is further coupledto a ram 208. The ram 208 is configured to be coupled to and drive thejaws 112A and 112B.

The piston head 203A divides an inside of the cylinder 108 into twochambers 210A and 210B. The chamber 210A is formed between the a surfaceof the piston head 203A that faces toward the ram 208, a surface of thepiston rod 203B, and a wall of the cylinder 108 at the first end 109A.The chamber 210B is formed between the a surface of the piston head 203Athat faces toward the motor 102 and the pump 104, the external surfaceof extension cylinder 206, and a wall of the cylinder 108 at the secondend 109B. Respective volumes of the chambers 210A and 210B vary as thepiston 200 moves linearly within the cylinder 108. The chamber 210Bincludes a portion of the extension cylinder 206.

The pump 104 is configured to draw fluid from a reservoir 214 topressurize the fluid and deliver the fluid to the extension cylinder206. The reservoir 214 may include fluid at a pressure close toatmospheric pressure, e.g., a pressure of 15-20 pounds per square inch(psi). Initially, the pump 104 provides low pressure fluid to theextension cylinder 206. The fluid has a path through the check valve 204to the extension cylinder 206. The fluid is blocked at high pressurecheck valve 212 and a release valve 216, which is coupled to, andactuatable by, the release lever 118.

The fluid delivered to the extension cylinder 206 applies pressure onarea A₁ within the piston 200. As illustrated, the area A₁ is a crosssection area of the extension cylinder 206. The fluid causes the piston200 and the ram 208 coupled thereto to advance rapidly. Particularly, ifthe flow rate of the fluid into the extension cylinder 206 is Q, thenthe piston 200 and the ram 208 move at a speed equal to V₁, where V₁could be calculated using the following equation:

$\begin{matrix}{V_{1} = \frac{Q}{A_{1}}} & (1)\end{matrix}$

Further, if the pressure of the fluid is P₁, then the force F₁ appliedon the piston 200 could be calculated using the following equation:

F₁=P₁A₁   (2)

Further, as the piston 200 extends within the cylinder 108, hydraulicfluid is pulled or drawn from the reservoir 214 through a bypass checkvalve 218 into the chamber 210B. As the piston 200 begins to extend,pressure in the chamber 210B is reduced below the pressure of the fluidin the reservoir 214, and therefore the fluid in the reservoir 214 flowsthrough the bypass check valve 218 into and the chamber 210B and fillsthe chamber 210B.

As the piston 200 and the ram 208 extend, the jaws 112A and 112B movetoward each other in preparation for cutting a cable placed therein. Asthe jaws 112A and 112B reach the cable, the cable resists their motion.Increased resistance from the cable causes pressure of the hydraulicfluid provided by the pump 104 to rise.

Referring back to FIG. 1, the tool 100 includes a sequence valve 120. Toillustrate operation of the sequence valve 120, FIG. 2B illustrates apartial cross section of a top view of the tool 100, in accordance withan example implementation. As shown in FIG. 2B, the sequence valve 120includes a poppet 220 and a ball 222 coupled to one end of the poppet220. A spring 224 pushes against the poppet 220 to cause the ball 222 toprevent flow through the sequence valve 120 until the fluid reaches apredetermined pressure set point that exerts a force on the ballexceeding the force applied by the spring 224 on the poppet 220. Forexample, the predetermined pressure set point that causes the sequencevalve 120 to open could be between 350 and 600 psi; however, otherpressure values are possible. This construction of the sequence valve120 is an example construction for illustration, and other sequencevalve designs could be implemented.

Once the pressure of the fluid exceeds the predetermined pressure setpoint, fluid pressure overcomes the spring 224 and the sequence valve120 opens, thus allowing the fluid to enter the chamber 210B. As such,the fluid now acts on an annular area A₂ of the piston 200 in additionto the area A₁. Thus, the fluid acts on a full cross section of thepiston 200 (A₁+A₂). For the same flow rate Q, used in equation (1), thepiston 200 and the ram 208 now move at a speed equal to V₂, where V₂could be calculated using the following equation:

$\begin{matrix}{V_{2} = \frac{Q}{A_{1} + A_{2}}} & (3)\end{matrix}$

As indicated by equation (3), V₂ is less than V₁ because of the increasein the area from A₁ to (A₁+A₂), and thus the piston 200 and the ram 208slow down to a controlled speed that achieves a controlled, more precisecutting or crimping operation. However, the pressure of the fluid hasincreased to a higher value, e.g., P₂, and thus the force applied on thepiston 200 also increases and could be calculated using the followingequation:

F ₂ =P ₂(A ₁ +A ₂)   (4)

F₂ is greater than F₁ because of the area increase from A₁ to (A₁+A₂)and the pressure increase from P₁ to P₂. Thus, when the sequence valve120 opens, high pressure hydraulic fluid can enter both the extensioncylinder 206 and the chamber 210B to cause the ram 208 to apply a largeforce that is sufficient to cut the cable or crimp a connector at acontrolled speed.

Referring back to FIG. 2A, higher pressure fluid is now filling thechamber 210B due the opening of the sequence valve 120. The highpressure fluid pushes a ball of the bypass check valve 218 causing thebypass check valve 218 to close, thus preventing fluid from the chamber210B to flow back to the reservoir 214. In other words, the bypass checkvalve 218 has fluid at reservoir pressure on one side and high pressurefluid in the chamber 210B on the other side. The high pressure fluidshuts off the bypass check valve 218, which thus does not allow fluid tobe drawn from the reservoir 214 into the chamber 210B.

Referring back to FIG. 1, the tool 100 includes a pressure sensor 122configured to provide sensor information indicative of pressure of thefluid. The pressure sensor 122 may be configured to provide the sensorinformation to a controller (not shown) of the tool 100.

The controller may include a processor, a memory, and a communicationinterface. The memory may include instructions that, when executed bythe processor, cause the controller to operate the tool 100. Thecommunication interface enables the controller to communicate withvarious components of the tool 100 such as the motor 102 and the sensor122.

Once the cable is cut or a connector is crimped and the piston 200reaches an end of its stroke within the cylinder 108, hydraulic pressureof the fluid increases because the motor 102 may continue to drive thepump 104. The hydraulic pressure may keep increasing until it reaches athreshold pressure value. In an example, the threshold pressure valuecould be 8500 psi; however, other values are possible. Once thecontroller receives information from the pressure sensor 122 that thepressure reaches the threshold pressure value, the controller may shutoff the motor 102.

The release lever 118 may then be actuated manually by an operator toretract the piston 200 and the ram 208 to a home or start position. FIG.2C illustrates another cross section of the side view of the tool 100showing retraction of the piston 200, in accordance with an exampleimplementation. The tool 100 includes a return spring 228 disposed inthe chamber 210A. The spring 228 is affixed at the end 109A of thecylinder 108 and acts on the surface of the piston head 203A that facestoward the piston rod 203B and the ram 208.

As illustrated in FIG. 2C, when the release lever 118 is actuated, thespring 228 pushes the piston head 203A back. Also, pressure of fluid inthe extension cylinder 206 and the chamber 210B is higher than pressurein the reservoir 214. As a result, hydraulic fluid is discharged fromthe extension cylinder 206 through the release valve 216 back to thereservoir 214 as indicated by the arrows in FIG. 2C. At the same time,hydraulic fluid is discharged from the chamber 210B through the highpressure check valve 212 and the release valve 216 back to the reservoir214, while being blocked by the check valve 218 and the check valve 204.Particularly, the check valve 204 prevents back flow into the pump 104.

FIGS. 2D, 2E, and 2F illustrate operation of the release lever 118 andthe release valve 216, in accordance with an example implementation. Theview shown in FIGS. 2D-2F is upside down compared to FIGS. 2B-2C, and isa zoomed view of a release mechanism including the release lever 118 andthe release valve 216.

As shown in FIG. 2D, the release valve 216 includes a valve ball 230 anda valve poppet or pin 232. A set screw 234 is coupled to the releaselever 118. The set screw 234 and the release lever 118 are configured todrive a lever 236, which is configured to push on the valve pin 232. Therelease mechanism illustrated in FIGS. 2D-2F provides a two stagerelease operation, and enhances the release operation as described next.

Referring to FIG. 2E, an operator pushes the release lever 118 in adirection of arrow 238 (i.e., to the right in FIG. 2E), thus causing theset screw 234 to push on the lever 236. The lever 236 in turn pushes onthe valve pin 232. The valve pin 232 moves the valve ball 230 off itsseat, releasing the high pressure by allowing high pressure fluid to goaround the now unseated valve ball 230 to the reservoir 214. Thisoperation requires high force due to the high fluid pressure forcing thevalve ball 230 into the seat.

To achieve this high force, it is noted that a hinge 240 of the releaselever 118 operates as a fulcrum. As shown in FIG. 2E, a horizontaldistance between the set screw 234 and the hinge (fulcrum) 240 is small,and thus the force that the set screw 234 applies on the lever 236 ishigh by virtue of the lever law of a fulcrum. A fulcrum equation can beused to express relationship between the force applied by the operatoron the release lever 118 and the force that the set screw 234 applies onthe lever 236 as follows:

F_(L)d_(L)=F_(SS)d_(SS)   (5)

where F_(L) is a force related to the force applied on the release lever118 by the operator, d_(L) is a distance between point of application ofthe force on the release lever and the hinge 240, F_(SS) is the forceapplied by the set screw 234 on the lever 236, and d_(SS) is a distancebetween the set screw 234 and the hinge 240.

As indicated by equation (5), the smaller the distance d_(SS), thehigher the force F_(SS) applied by the set screw 234 on the lever 236assuming F_(L) and d_(L) are constant. Thus, when the release lever 118is initially pushed by the operator, a high force F_(SS) is applied bythe set screw 234 to overcome the high pressure fluid pushing on thevalve ball 230. However, the distance moved by the set screw 234 in adirection of arrow 242 is small.

Once the release lever 118 moves far enough, the set screw 234 losescontact with the lever 236 as shown in FIG. 2F. Thereafter, a protrusion244 coupled to the release lever 118 contacts the lever 236. A fulcrumequation can be used to express relationship between the force appliedby the operator on the release lever 118 and the force that theprotrusion 234 applies on the lever 236 as follows:

F_(L)d_(L)=F_(P)d_(P)   (6)

where F_(P) is the force applied by the protrusion 244 on the lever 236,and d_(P) is a distance between the protrusion 244 and the hinge 240.

As indicated by FIGS. 2E and 2F, the distance d_(p) is larger than thedistance d_(SS). Thus, although the force F_(P) applied by theprotrusion 244 on the lever 236 is less than the force F_(SS), thedistance or stroke moved by the protrusion 244 is larger than thedistance or stroke moved by the set screw 234. This larger stroke allowsthe valve ball 230 to be moved farther off the seat, thus increasingflow to the reservoir 214 and reducing return time for the ram 208.

Thus, the construction of the release lever 118 as shown in FIGS. 2D-2F,allows the release lever 118 to have two stages of operation. The firststage facilitates applying a high force by the set screw 234 on thelever 236 to initially break the fluid pressure applied on the valveball 230, but allows the set screw 234 to move a small distance orstroke. The second stage facilitates applying a low force by theprotrusion 244 on the lever 236, but allows the protrusion 244 to have alarger stroke compared to the stroke of the set screw 234 to increaseflow through the release valve 216.

Referring back to FIG. 1, if the pressure sensor 122 fails, hydraulicfluid pressure within the tool 100 may increase to unsafe levels becausethe controller might not receive information indicating the pressure ofthe fluid and might not shut off the motor 102 when pressure exceeds athreshold. Thus, a relief valve could be added to the tool 100 torelieve pressure if the pressure sensor 122 fails and the controllerdoes not shut off the motor 102.

However, to save space and reduce weight and cost, the tool 100illustrated herein includes a burst disk 246 shown in FIG. 2B is used toprevent an over pressure situation. Specifically, if controller does notshut off the motor 102 and the motor 102 continues to run and buildhydraulic pressure within the tool 100, the burst disk 246 would ruptureand open up at a pre-determined or threshold pressure. For example, thispredetermined or threshold pressure that would rupture the burst disk246 could be 15000 psi; however, other pressure values are possible. Inthis manner, hydraulic fluid would have a path to the reservoir 214through the ruptured burst disk 246, and pressure would be relieved.

IV. Hydraulic Circuit

FIG. 3 illustrates a hydraulic circuit 300 of the hydraulic tool 100, inaccordance with an example implementation. Operation of the tool 100 asdescribed above can be summarized using the hydraulic circuit 300.

In an example, the tool 100 may include a trigger that could, forinstance, be coupled to a handle of the tool 100. When an operator ofthe tool 100 depresses the trigger, the controller of the tool 100receives a signal from the trigger and turns the motor 102 on. The motor102 drives the pump 104, which draws fluid from the reservoir 214through an intake check valve 302, pressurizes the fluid, and providesthe fluid through the check valve 204 to the extension cylinder 206.

Pressure of the fluid builds as a result of the resistance applied tomotion of the ram 208 from the cable or crimp connector as the motor 102continues to drive the pump 104, but initially, the pressure of thefluid is relatively low. At low pressure, hydraulic fluid can onlyaccess the extension cylinder 206 and cause the piston 200 and the ram208 to extend rapidly because the fluid acts on a small area (A ₁) . Theforce applied on the piston 200, however, is relatively small isindicated by equation (2) above.

As the ram 208 extends, hydraulic fluid is pulled from the reservoir 214into the chamber 210B within the cylinder 108 through the bypass checkvalve 218, to ensure that the chamber 210B fills with hydraulic fluid.However, the high pressure check valve 212 prevents high pressurehydraulic fluid discharged from the pump 104 from entering the chamber210B. The piston 200 and the ram 208 extend rapidly until the jaws 112Aand 112B shown in FIG. 1 contact a cable placed therebetween.

As cable cutting starts, the cable resists motion of the jaws 112A and112B, and thus resists extension of the ram 208. Consequently, hydraulicpressure rises in the system. Once the pressure exceeds a predeterminedthreshold or set point determined by spring rate of the spring 224 ofthe sequence valve 120, the sequence valve 120 will open, allowing highpressure hydraulic fluid discharged from the pump 104 to enter thechamber 210B.

The fluid now acts on an area equal to (A₁+A₂), or the full crosssection of the piston 200. Thus, the speed of extension of the piston200 decreases as indicated by equation (3), whereas the force that thepiston 200, and the jaws 112A-B, exerts increases as indicated byequation (4). Therefore, the area and volume of the extension cylinder206 is minimized to provide a rapid advance at low pressure, whereas thearea in the chamber 210B is maximized to provide maximum force at highpressure and controlled cut speed.

Once the cable is cut and the piston 200 and the ram 208 reach the endof stroke, the piston 200 becomes dead-headed and hydraulic pressureincreases until it reaches a threshold or set point pressure. Thepressure sensor 122 provides information to the controller of the tool100, and the controller shuts off the motor 102, and the pump 104 stopsproviding pressurized fluid.

The release lever 118 could then be actuated by the operator to actuatethe release valve 216 and retract the piston 200 and the ram 208 back tothe start or home position. When the release lever 118 is actuated,hydraulic fluid flows from the extension cylinder 206 through therelease valve 216 back to the reservoir 214, while being blocked by thecheck valve 204. At the same time, hydraulic fluid flows from thechamber 210B through the high pressure check valve 212 and the releasevalve 216 back to the reservoir 214, while being blocked by the checkvalve 218 and the check valve 204. Particularly, the check valve 204prevents back flow into the pump 104.

The burst disk 246 is used to prevent an over pressure situation. If themotor 102 would continue to run and build hydraulic pressure, the burstdisk 246 would open up at a pre-determined pressure, allowing hydraulicfluid to return back to the reservoir 214.

V. Conclusion

It should be understood that arrangements described herein are forpurposes of example only. As such, those skilled in the art willappreciate that other arrangements and other elements (e.g., machines,interfaces, orders, and groupings of operations, etc.) can be usedinstead, and some elements may be omitted altogether according to thedesired results.

While various aspects and implementations have been disclosed herein,other aspects and implementations will be apparent to those skilled inthe art. The various aspects and implementations disclosed herein arefor purposes of illustration and are not intended to be limiting, withthe true scope being indicated by the following claims, along with thefull scope of equivalents to which such claims are entitled. It is alsoto be understood that the terminology used herein is for the purpose ofdescribing particular implementations only, and is not intended to belimiting.

What is claimed is:
 1. A tool comprising: a hydraulic actuator cylinder;a piston slidably accommodated within the hydraulic actuator cylinder,wherein the piston includes a piston head and a piston rod extendingfrom the piston head along a central axis direction of the hydraulicactuator cylinder, wherein the piston head divides an inside of thehydraulic actuator cylinder into a first chamber and a second chamber,wherein the piston is partially hollow, and wherein the piston rod isdisposed in the first chamber and configured to move one or more jaws ofthe tool; a pump configured to provide pressurized fluid; and a sequencevalve configured to block the pressurized fluid from flowing into thesecond chamber of the hydraulic actuator cylinder until pressure of thepressurized fluid exceeds a threshold pressure value, wherein when thetool is triggered: the pump provides the pressurized fluid to a hollowportion of the piston, causing the piston to extend at a first speeduntil at least one of the one or more jaws reach an object placedtherebetween, and thereafter, pressure of the pressurized fluidincreases until the pressure reaches the threshold pressure value,causing the sequence valve to open providing a path for the pressurizedfluid to the second chamber, causing the piston to extend at a secondspeed.
 2. The tool of claim 1, wherein the hydraulic actuator cylinderhas a first end proximate to the one or more jaws and a second endopposite the first end, wherein the first chamber is formed between thepiston head, the piston rod, and the first end of the hydraulic actuatorcylinder, and wherein the second chamber is formed between the pistonhead and the second end of the hydraulic actuator cylinder.
 3. The toolof claim 1, further comprising: an extension cylinder disposed withinthe partially hollow piston, wherein the extension cylinder is affixedto the hydraulic actuator cylinder at the second end, wherein the pistonis configured to slide axially about an external surface of theextension cylinder as the piston extends, and wherein the pump providesthe pressurized fluid to the hollow portion of the piston through theextension cylinder, causing the piston to extend at the first speed. 4.The tool of claim 3, wherein the second chamber includes a portion ofthe extension cylinder.
 5. The tool of claim 1, further comprising: abypass check valve; and a reservoir containing fluid having a respectivepressure less than the pressure of the pressurized fluid, wherein, asthe piston extends at the first speed, the bypass check valve allowsfluid to be drawn from the reservoir into the second chamber to fill thesecond chamber.
 6. The tool of claim 1, further comprising: a highpressure check valve configured to prevent the pressurized fluid fromflowing into the second chamber as the piston extends at the firstspeed.
 7. The tool of claim 1, wherein when the sequence valve opens,the pressurized fluid flows into both the hollow portion and the secondchamber.
 8. The tool of claim 1, wherein the threshold pressure value isa first threshold pressure value, the tool further comprising: a motorconfigured to drive the pump; a pressure sensor configured to providesensor information indicative of the pressure of the pressurized fluid;and a controller in communication with the motor and the pressuresensor, and configured to receive the sensor information from thepressure sensor, wherein the controller is configured to shut-off themotor when the sensor information indicates that the pressure hasexceeded a second threshold pressure value.
 9. The tool of claim 8,wherein the pressure reaches the second threshold pressure value afterthe piston reaches an end of stroke of the piston within the hydraulicactuator cylinder.
 10. The tool of claim 1, further comprising: amanually operated release lever; and a release valve actuatable by therelease lever, wherein actuation of the release lever actuates therelease valve, causing the release valve to provide a respective pathfor fluid within the hollow portion and the second chamber to flow backto a reservoir containing respective fluid having a respective pressureless than the pressure of the pressurized fluid.
 11. The tool of claim10, wherein the release valve comprises a valve pin coupled to a valveball, and wherein actuation of the release lever moves a lever coupledto the valve pin to apply a force on the valve pin to move the valveball off of a seat of the valve ball and provide the respective path forthe fluid within the hollow portion.
 12. The tool of claim 11, whereinthe manually operated release lever is coupled to the tool by way of ahinge operable as a fulcrum, wherein the manually operated release levercomprises a screw and a protrusion, wherein the screw is closer to thehinge than the protrusion, such that the screw initially applies a firstforce on the lever, then loses contact with the lever as the protrusioncontacts the lever to apply a second force on the lever, and wherein thesecond force is less than the first force.
 13. The tool of claim 1,wherein the threshold pressure value is a first threshold pressurevalue, the tool further comprising: a burst disk in fluid communicationwith the pressurized fluid, wherein the burst disk is configured torupture when the pressure of the pressurized fluid exceeds a secondthreshold pressure value, and wherein the ruptured burst disk provides arespective path for the pressurized fluid to flow back to a reservoircontaining respective fluid having a respective pressure less than thepressure of the pressurized fluid.
 14. The tool of claim 1, furthercomprising: a frame and a bore formed therein, wherein the frame and thebore form the hydraulic actuator cylinder.
 15. A hydraulic circuit,comprising: a hydraulic actuator cylinder; a piston slidablyaccommodated within the hydraulic actuator cylinder, wherein the pistonincludes a piston head and a piston rod extending from the piston headalong a central axis direction of the hydraulic actuator cylinder,wherein the piston head divides an inside of the hydraulic actuatorcylinder into a first chamber and a second chamber, wherein the pistonis partially hollow, and wherein the piston rod is disposed in the firstchamber; a pump configured to provide pressurized fluid; and a sequencevalve configured to block the pressurized fluid from flowing into thesecond chamber of the hydraulic actuator cylinder until pressure of thepressurized fluid exceeds a threshold pressure value, wherein: the pumpprovides the pressurized fluid to a hollow portion of the piston,causing the piston to extend at a first speed until the piston rod meetsa resistance, and thereafter, pressure of the pressurized fluidincreases until the pressure reaches the threshold pressure value,causing the sequence valve to open providing a path for the pressurizedfluid to the second chamber, causing the piston to extend at a secondspeed.
 16. The hydraulic circuit of claim 15, wherein the hydraulicactuator cylinder has a first end proximate to the one or more jaws anda second end opposite the first end, wherein the first chamber is formedbetween the piston head, the piston rod, and the first end of thehydraulic actuator cylinder, and wherein the second chamber is formedbetween the piston head and the second end of the hydraulic actuatorcylinder.
 17. The hydraulic circuit of claim 15, further comprising: anextension cylinder disposed within the partially hollow piston, whereinthe extension cylinder is affixed to the hydraulic actuator cylinder atthe second end, wherein the piston is configured to slide axially aboutan external surface of the extension cylinder as the piston extends, andwherein the pump provides the pressurized fluid to the hollow portion ofthe piston through the extension cylinder, causing the piston to extendat the first speed.
 18. The hydraulic circuit of claim 17, wherein thesecond chamber includes a portion of the extension cylinder.
 19. Thehydraulic circuit of claim 14, further comprising: a bypass check valve;and a reservoir containing fluid having a respective pressure less thanthe pressure of the pressurized fluid, wherein, as the piston extends atthe first speed, the bypass check valve allows fluid to be drawn fromthe reservoir into the second chamber to fill the second chamber. 20.The hydraulic circuit of claim 19, further comprising: a high pressurecheck valve configured to prevent the pressurized fluid from flowinginto the second chamber as the piston extends at the first speed. 21.The hydraulic circuit of claim 20, further comprising: a manuallyoperated release lever; and a release valve actuatable by the releaselever, wherein actuation of the release lever actuates the releasevalve, causing the release valve to provide a respective path for fluidwithin the hollow portion to flow back to the reservoir.
 22. Thehydraulic circuit of claim 15, wherein when the sequence valve opens,the pressurized fluid flows into both the hollow portion and the secondchamber.